@Relaxing RitaSintra is WONDERFUL but, being there is 4 of you and your time is limited, I would recommend a taxi once you arrive in Sintra. The tourist train is fine UNLESS there are crowds waiting for it which is what happened to us. An entire school group was waiting. Taxis are not allowed to pick up random passengers from the sites (which we didn't know) so we had to make arrangements "on the quiet" with a driver who was waiting for his regular customers to complete their tour. This necessitated us walking a ways down the hill in order to meet up with him. Follow the advice from edinburgher and see if you can find a taxi tour you can arrange in advance and, since your time IS limited, decide what you really want to see because you just don't have time to see everything.